Liquid atomizer



United States Patent 3,206,124 LIQUID ATGMIZER William L. Drayer and Sulo A. Makeia, Warren, Mich, assignors to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed Feb. 4, 1964, Ser. No. 342,345 8 Claims. (Cl. 239-102) This is a continuation-in-part of our application, Serial Number 214,653, filed August 3, 1962, entitled Liquid Atomizer, now abandoned.

This invention concerns a liquid atomizer in which pressurized air is utilized for moving a diaphragm at a high frequency to mechanically atomize liquid from the surface of the diaphragm.

In a copending application identified as Serial Number 159,313, filed December 14, 1961 in the name of William L. Drayer, and assigned to the assignee of this invention, an atomizer is disclosed in which a diaphragm is supported in a housing and has a rod centrally connected at one end to the diaphragm. The free end of the rod is associated with a fluid driven vibrator, and upon energization of the latter, vibratory energy is transmitted to the diaphragm through the rod causing a flexing action of the diaphragm which serves to atomize and disperse any liquid deposited on the outer surface of the diaphragm. This atomizer is a marked improvement over prior diaphragm type atomizers in that the vibrator is of simple and durable construction and eihcient in operation. However, the fact that a separate vibrating unit must be combined with the diaphragm constitutes an expense that if eliminated could greatly decrease the cost of and simplify the manufacture and assembly of the atomizer.

Accordingly, one object of the present invention is to provide a diaphragm type atomizer in which the diaphragm does not require any auxiliary vibratory unit for developing vibrations in the diaphragm.

Another object of this invention is to provide a diaphragm type atomizer in which a differential pressure exists at one surface of a diaphragm causing a valving action on a compressible fluid so as to vibrate the dia phragm at the resonant frequency of the latter and thereby atomize liquid deposited on the outer surface of the diaphragm.

The above objects and others are accomplished with an atomizer having a housing which supports a diaphragm adjacent the periphery thereof and coacts with the housing so as to define a fluid chamber. A pair of openings in the housing connect the chamber with a source of differential pressure and one of the openings is provided with an adjustable fluid conduit. One end of the fluid conduit is disposed proximate the diaphragm and lie in a plane parallel thereto so that upon adjustment of the conduit, the distance between the conduit and the inner surface of the diaphragm can be varied. The other opening is connected to a source of pressurized air which causes the diaphragm to move away from and toward the fluid conduit so as to respectively open and close the conduit at a high frequency with the result that liquid deposited on the outer surface of the diaphragm is atomized into fine particles.

A more complete understanding of the invention can be derived from the following detailed description taken in conjunction with the accompanying drawings in which:

FIGURE 1 is a sectional view of an atomizer constructed in accordance with the invention;

FIGURE 2 is a view of the atomizer of FIGURE 1 taken on line 2-2.

Referring now to the drawings, FIGURE 1 shows an atomizer constructed in accordance with the invention rigidly fixed at the side portions thereof in a passage communicating with a vehicle intake manifold wherein liquid fuel can be atomized and directed therefrom to the several combustion chambers of an internal combustion engine.

More specifically, the atomizer comprises a housing having a base portion 10 with a ring-type member 12 secured thereto by a plurality of cap screws one of which is indicated by the numeral 14. A circular diaphragm or disk member 16 made from a thin sheet of spring steel or plastic is interposed between the ring-type member 12 and the base portion 10 and is rigidly retained therebetween by the aforementioned screws. The diaphragm cooperates with the base portion 10 to define an annular fluid chamber 18, which connects with a source 20 of pressurized air through an opening 22 formed in the lower portion of the base. A valve 21 is provided in the air line between the source 20 and the atomizer so as to control the flow of compressed air.

Adjacent the opening 22 and mounted centrally within the base is an externally threaded fluid conduit 24 having an upper end 26 and a slotted lower end 27 which permits the conduit to be rotated with an appropriate tool to vertically position the conduit in a threaded base bore 28. The purpose of this adjustment is to vary the distance between the fluid conduit upper end 26, which lies in a plane parallel to the diaphragm, and the lower surface of the diaphragm 16. This provides a predetermined restriction on the fluid passage formed in the conduit 24 and serves a function which will hereinafter be described. Above the diaphragm a liquid nozzle 30 is provided that connects with a source of liquid fuel 32 that delivers a metered amount of liquid fuel to the diaphragm surface as dictated by the valve regulator 34.

During engine operation, liquid fuel is supplied to the outer surface of the diaphragm 16 by the nozzle 30 and simultaneously, pressurized air from the source 2Q is directed to the fluid chamber 18 of the atomizer under the control of the valve 21. The pressurized air causes the diaphragm to move in a direction away from the upper end 26 of the fluid conduit 24 thereby diminishing the restrictive eflect of the diaphragm on the passage formed in the conduit 24 and permitting the pressurized air to exhaust via the passage in the conduit. Thereupon, the spring steel diaphragm is under the influence of a restoring force due to the inherent resiliency of the metal so as to cause the diaphragm to return to its initial position and again substantially close the upper end of the fluid conduit. Once again, pressurized air fills the chamber 13 to move the diaphragm upwardly and the cycle is repeated.

As aforementioned, the fluid conduit 24 can be rotated at the slotted end 27 so as to adjustably vary the distance between the upper end 26 of the conduit and the inner surface of the diaphragm. During test runs of atomizers of the subject type, it was possible to vary the frequency of the vibrating diaphragm between 200 and 4,000 cycles per second. Of course, the frequency of vibration can be increased or decreased beyond the limits mentioned by dimensional changes in the diaphragm and/or in the size of the fluid conduit. However, for optimum atomization the diaphragm should be vibrated at a frequency above 1900 cycles per second and preferably at the resonant frequency of the diaphragm in order to realize maximum deflections. Moreover, it has been found that the differential pressure existing between the chamber 18 and the passage in the fluid conduit need not be more than /1 to 2 p.s.i. in order to obtain the frequency of vibration required for atomization. Hence, this atomizer adapts itself well for use with internal combustion engines inasmuch as it can be operated by the intake manifoid vacuum. In this regard, it should be noted that '33 when the atomizer is to be operated by vacuum, the opening 22 and the passage in the fluid conduit 24 would be connected with atmosphere and the manifold vacuum, respectively.

One atomizer tested and found to give extremely fine atomization utilized a diaphragm having a thickness of .010 inch and a working diameter of 2.0 inches so as to give an exposed surface area of 3.14 square inches. The passage in the fluid conduit 24 had a diameter of 0.50 inch and the distance between the under surface of the diaphragm and the opposite parallel wall was 0.12 inch.

Various changes and modifications can be made in the subject atomizer without departing from the spirit of the invention. It should be understoodthat these changes and modifications are contemplated and we do not wish to be limited beyond the scope of the appended claims.

What is claimed is:

1. An atomizer comprising a diaphragm mounted in a housing so as to define a fluid chamber, said housing having inlet and outlet ports formed therein and communicating with said chamber, one of said ports terminating within said chamber, means for depositing a liquid on the outer surface of the diaphragm, a source of pressurized air, and means for directing said air to said chamher through one of the ports so that said diaphragm is alternately moved away from and toward said port terminating in the chamber to respectively open and close said port at the resonant frequency of the diaphragm to atomize the liquid from the outer surface of the diaphragm.

2. An atomizer comprising a diaphragm mounted in a housing so as to define a chamber, said housing having inlet and outlet ports formed therein and communicating with said chamber, one of said ports having a fluid conduit with one end thereof terminating Within said fluid chamber, a source of liquid, means connected to the source for depositing the liquid on the outer surface of the diaphragm, a source of pressurized air, and means for connecting said air to said chamber through one of the ports so that said diaphragm is alternately moved away from and toward said one end of the fluid conduit to respectively open and close the conduit at the resonant frequency of the diaphragm to atomize the liquid from the outer surface of the diaphragm.

3. An atomizer comprising a planar diaphragm moun ed adjacent the periphery thereof in a housing so as to define a chamber, said housing having inlet and outlet openings formed therein for communicating with said chamber, a fluid conduit threaded into one of the openings and having one end thereof terminating proximate the inner surface of the diaphragm, means for depositing a liquid on the outer surface of the diaphragm, a source of pressurized air, and means for directing said air to said chamber through one of the openings so that said diaphragm is alternately moved away and toward said fluid conduit end to open and close said end at a resonant frequency of the diaphragm so as to atomize the liquid from the outer surface of the diaphragm.

4. An atomizer comprising a diaphragm supported adjacent the periphery thereof in a housing so as to define a chamber, said housing having a first and second opening formed therein, a fluid conduit supported by the first opening, one end of the conduit terminating in a plane parallel to and proximate the inner surface of the diaphragm and being located centrally with respect to the periphery of the diaphragm, means for depositing a liquid on the outer surface of the diaphragm, and a source of pressurized air connected to one of the openings for directing the air to the chamber so that the diaphragm alternately moves away from and towards said end of the conduit to respectively open and close said end at a resonant frequency of the diaphragm so as to atomize the liquid from the other surface of the diaphragm.

5. The device of claim 4 wherein means are provided so that said fluid conduit is adjustably supported inthe opening to vary the distance between the said end of the conduit and the inner surface of the diaphragm.

6. An atomizer comprising a diaphragm, means for supporting the peripheral edge of the diaphragm, a first and second passage formed in said means for connecting one surface of the diaphragm to a differential pressure, said diaphragm being movable alternately at the resonant frequency thereof towards and away from one of said passages when the other passage is at a pressure greater than said one of said passages, and means for depositing a liquid on said diaphragm to be atomized by the movement of the diaphragm.

7. An atomizer comprising a diaphragm, means for supporting the peripheral edge of the diaphragm, a first and second passage formed in said means, one of said passages being at a controlled air pressure greater than the other so as to cause the diaphragm to alternately raise away from and towards the other passage at the resonant frequency of the diaphragm, and means for depositing a iquid on said diaphragm to be atomized by the movement of the diaphragm.

8. An atomizer comprising a diaphragm, means for.

supporting the peripheral edge of the diaphragm, a first and second fluid passage formed in said means, a source of pressurized air, the first passage connecting an annular portion of the diaphragm inner surface to the source of pressurized air, the second passage connecting the remainder of the diaphragm inner surface to atmosphere, means for controlling the flow of said pressurized air to cause said diaphragm to move alternately away fromand towards the second passage so as to substantially open and close the latter respectively at the resonant frequency of the diaphragm, and means for directing liquid to the moving diaphragms to be atomized therefrom.

References Cited by the Examiner UNITED STATES PATENTS 2,646,039 7/53 Agosti. 2,812,612 11/57 Vang 239-l02 EVERETT W. KIRBY, Primary Examiner. 

7. AN ATOMIZER COMPRISING A DIAPHRAGM, MEANS FOR SUPPORTING THE PERIPHERAL EDGE OF THE DIAPHRAGM, A FIRST AND SECOND PASSAGE FORMED IN SAID MEANS, ONE OF SAID PASSAGES BEING AT A CONTROLLED AIR PRESSURE GREATER THAN THE OTHER SO AS TO CAUSE THE DIAPHRAGM TO ALTERNATELY RAISE AWAY FROM AND TOWARDS THE OTHER PASSAGE AT THE RESONANT FREQUENCY OF THE DIAPHRAGM, AND MEANS FOR DEPOSITING A LIQUID ON SAID DIAPHRAGM TO BE ATOMIZED BY THE MOVEMENT OF THE DIAPHRAGM. 